Such actuating units and process valves are known from the prior art and are offered on the market in a wide variety of variants.
On the one hand, the diversity of variants results from the use of actuating units for process valves and of process valves in a wide range of applications having different requirements. Furthermore, actuating units and process valves having different properties are also required within a specific field of application.
Process valves which are closed in the absence of a control signal (so-called “normally closed” valves, abbreviated: NC valve) may for example be required within an application. Process valves which are open in the absence of a control signal (so-called “normally open” valves, abbreviated NO valve) may additionally be required in the same application. The control signal is in particular an electrical or pressure fluidic, i.e. hydraulic or pneumatic signal. The absence of a control signal may thus also be referred to a currentless or pressureless state. These characteristics are usually implemented within an actuating unit of a process valve. This means that a process valve may be configured as an NC or NO valve by being equipped with an appropriate actuating unit.
A further exemplary variant-creating characteristic of actuating units and process valves is the optional presence of spring-loaded valve elements. Due to the spring load, the NC or NO valves are provided with a spring-loaded valve element which urges the valve element into the closed or open position.
A further example is the realization of process valves as switching or control valves. Switching valves are often referred to as on/off valves. Control valves are also called proportional valves or continuously adjustable valves. Usually, these functionalities are also implemented in actuating units of process valves. A control valve differs from a switching valve in that in this valve, the transition from a valve position to another valve position may be realized in a continuous manner. It can take up any intermediate position. It is thus for example possible to adjust half of a flow rate via half of the piston stroke. A switching valve however can substantially take up only discrete valve positions. Usually, it does not permit any intermediate position.
This wide variety of variants causes high expenditures in the manufacture of the process valves and the associated actuating units. This applies among others to the associated production logistics and the subordinate stockkeeping of finished actuating units and process valves.
Therefore, the object of the present invention is to provide process valves and actuating units for process valves, by means of which the expenditure in the manufacture of such process valves and actuating units may be reduced while keeping the diversity of variants as required on the application side.